Natural and chemosynthesis antimicrobial agents and antifungal agents for agriculture are being studied. Some of the antimicrobial agents and antifungal agents for agriculture are put on the market. However, antimicrobial agents and antifungal agents for agriculture, which are in use at present, cannot adequately cope with phytopathogens because of agents having different sensitivities to phytopathogens, phytopathogens becoming resistive to agents, agent-induced sufferings, or the like. In this respect, there is a demand of developing safer and more effective agents in the field of antimicrobial agents and antifungal agents for agriculture.
As natural antimicrobial agents, acetic acid, machine oil, rapeseed oil or the like are put in practical use.
As chemosynthesis antimicrobial agents, benzimidazole antimicrobial agents, such as a thiophanate methyl agent, sterol biosynthesis inhibitors, such as a triadimefon agent and biterthanol agent, anilino pyrimidine microbicide, such as pyrimethanil agent, or the like are put in practical use.
Powdery mildew or the like is caused as conidia fly around in the air, adhere to tomatoes, cucumbers or the like and germinate.
There are air cleaners which remove bacteria, spore, and pollen or the like in the air. The air cleaners which remove bacteria, spore, pollen, or the like, with a filter and/or with electrostatic precipitation are known.
The filter type is not effective unless it has smaller apertures than what is removed, and is difficult to run over a long period of time due to clogging.
An electrostatic induction dust collecting apparatus using two metal electrodes and a plastic three-dimensional mesh screen placed in parallel thereto has been reported as one which increases the effect of capturing dust or mist floating in the air (for example, see Patent Document 1).
An electric dust collecting apparatus of a wire discharge type which applies a high voltage to a metal wire, and an electric dust collecting apparatus of a needle discharge type which applies a high voltage to the tip of a needle are further known (for example, see Patent Document 2, Patent Document 3, and Patent Document 4, or the like). Both of them remove bacteria, spore, pollen, or the like by charging the spore, pollen, or the like to be removed with corona discharge, and making it adsorbed by a collecting electrode.
Diseases and insect damages of vegetables or ornamental flowers if occurred in a greenhouse are very likely to occur on all the plants in the greenhouse. This risk is therefore avoided by pesticide spray before occurrence of diseases and insect damages. It is however difficult, at present, to suppress occurrence of diseases and insect damages of plants without depending on such pesticide spray.
The electrostatic induction dust collecting apparatus which uses metal electrodes and a plastic three-dimensional mesh screen placed in parallel thereto may have corona discharge at the exposed metal electrodes.
While the electric dust collecting apparatus charges spore, pollen, or the like using corona discharge or so, it produces ozone. Accordingly, ozone is likely to adversely affect the plants. Further, the charging efficiency may drop under the condition of a high humidity.    [Patent Document 1] JP-A-52-120473    [Patent Document 2] JP-A-10-137628    [Patent Document 3] JP-A-2000-189835    [Patent Document 4] JP-A-2003-211024